package com.lbc.binarysearchnorecursion;

public class BinarySearchNoRecur {
    public static void main(String[] args) {
        //  测试
        int[] arr = {1,3,8,10,11,67,100};
        int target = 10;
        int index = binarySearch(arr, target);
        System.out.println(index);
    }

    /**
     *   二分查找的非递归实现
     * @param arr  待查找的数组
     * @param target  需要查找的数
     * @return  返回对应的下标，-1表示没有找到
     */
    public static int binarySearch(int[] arr, int target) {
        int left = 0;
        int right = arr.length - 1;
        while (left <= right) {  //  说明继续查找
            int mid = (left + right) / 2;
            if (arr[mid] == target) {
                return mid;
            } else if (arr[mid] > target) {
                right = mid -1;  //  需要向左查找
            } else {
                left = mid + 1;  //  需要向右查找
            }
        }
        return -1;
    }
}
